Toward a Consistent Description of the PNC Experiments in A=18-21 Nuclei

Abstract

The experimental PNC results in ${}^{18}$F, ${}^{19}$F, ${}^{21}$Ne and the current theoretical analysis show a discrepancy . If one interprets the small limit of the experimentally extracted PNC matrix element for ${}^{21}$Ne as a destructive interference between the isoscalar and the isovector contribution, then it is difficult to understand why the isovector contribution in ${}^{18}$F is so small while the isoscalar + isovector contribution in ${}^{19}$F is relatively large. In order to understand the origin of this discrepancy a comparison of the calculated PNC matrix elements was performed. It is shown that the ${}^{18}$F and ${}^{21}$Ne matrix elements contain important contributions from 3$\hslash \omega$ and 4$\hslash \omega$ configuration and that the (0+1)$\hslash \omega$ calculations give distorted results.

Comments: REVTEX, 16 pages, 1 postscriptum figure uuencoded and appended